H-1-NMR SIGNAL OF ARENICOLA-MARINA MYOGLOBIN IN-VIVO AS AN INDEX OF TISSUE OXYGENATION

Key questions on how intertidal animals adapt to hypoxic stress center on the high energy phosphate response to decreasing oxygenation. With recent H-1/P-31-NMR techniques to monitor mammalian tissue metabolism , a novel approach has emerged to observe potentially the intracellula r oxygen interaction in invertebrates. The present study indicates tha t Arenicola marina, a standard model for intertidal animals, exhibits a distinct set of Mb H-1-NMR signals ill vivo, corresponding to the tw o isolated Mb isoforms. Specifically both deoxy-Mb I and deoxy-Mb II e xhibit paramagnetically shifted signals at 93.4 ppm and 92.5 ppm at 25 degrees C, respectively, which arise from the proximal histidyl Ndelt aH. These signals reflect the cellular oxygenation slate and indicate clearly that the phosphotaurocyamine level begins to drop al the onset of anoxia and declines gradually to 50% of control after 3.5 h. H-1 M b spectra indicate protein heterogeneity originating from heme as well as structural disorder.